FIGS. 4(a) and 4(b) are a plan view and a cross-sectional view of a power semiconductor module according to a related art, respectively. FIG. 4(b) is a cross-sectional view of a main part taken along line III-III in FIG. 4(a).
In FIGS. 4(a) and 4(b), a power semiconductor module 500 includes a direct copper bonding (DCB) substrate 104, a semiconductor element 106, a post electrode 108, an external terminal 110, and a printed circuit board 109.
The DCB substrate 104 has a circuit plate 103 formed on a principal surface thereof. The rear surface of the semiconductor element 106 is fixed to the circuit plate 103 by a bonding material 105. The post electrode 108 is fixed to a front surface of the semiconductor element 106 by a bonding material 107. The external terminal 110 is fixed to an external terminal insertion recess 112 formed in the circuit plate 103 by a conductive bonding material (not illustrated). The printed circuit board 109 has a metal layer 114 and the post electrode 108 is fixed thereto.
The power semiconductor module 500 has a structure in which an electric wire for connection to a rear-surface electrode (not illustrated) of the semiconductor element 106 is formed on the circuit plate 103, and an electric wire for connection to a front-surface electrode (not illustrated) of the semiconductor element 106 is formed on the printed circuit board 109 having the post electrode 108 and the metal layer 114 (for example, see Patent Literature 1).
FIGS. 5(a) to 5(c) illustrate the steps of manufacturing the power semiconductor module 500.
FIGS. 5(a) to 5(c) are schematic views illustrating the steps of manufacturing the power semiconductor module according to the related art, and FIG. 6 is an enlarged plan view of a through-hole according to the related art.
First, the conductive bonding material 105 such as a solder is placed on the DCB substrate 104. After that, the semiconductor element 106 is placed thereon, and the conductive bonding material 107 such as a solder is placed thereon (FIG. 5(a)). Subsequently, the external terminal 110 is inserted in the recess 112 formed on a surface of the DCB substrate 104 to which the semiconductor element 106 is bonded (FIG. 5(b)). Further, the printed circuit board 109 in which the surface of the post electrode 108 faces the DCB substrate 104 is set by inserting the external terminal 110 into the through-hole 113 formed in the printed circuit board 109 (FIG. 5(c)). This module is assembled collectively according to, for example, N2.H2 reflow and is finally manufactured by sealing the same with a resin. In this method, since the external terminal 110 is guided using the through-hole 13, the alignment of the printed circuit board 109 can be made without using a jig (for example, see Patent Literature 2).
Here, FIG. 6 illustrates an enlarged plan view of a printed circuit board and an external terminal insertion through-hole having a circular cross-sectional shape.
An inner diameter of the through-hole 113 formed in the printed circuit board 109 is approximately the same (up to +0.05 mm) as the outer diameter of the external terminal 110.